#pragma once

namespace base {

// Do not declare a NotificationDetails directly--use either
// "Details<detailsclassname>(detailsclasspointer)" or
// NotificationService::NoDetails().
class NotificationDetails {
public:
  NotificationDetails() : ptr_(NULL) {}
  NotificationDetails(const NotificationDetails &other) : ptr_(other.ptr_) {}
  ~NotificationDetails() {}

  // NotificationDetails can be used as the index for a map; this method
  // returns the pointer to the current details as an identifier, for use as a
  // map index.
  uintptr_t map_key() const { return reinterpret_cast<uintptr_t>(ptr_); }

  bool operator!=(const NotificationDetails &other) const {
    return ptr_ != other.ptr_;
  }

  bool operator==(const NotificationDetails &other) const {
    return ptr_ == other.ptr_;
  }

protected:
  explicit NotificationDetails(const void *ptr) : ptr_(ptr) {}

  // Declaring this const allows Details<T> to be used with both T = Foo and
  // T = const Foo.
  const void *ptr_;
};

template <class T> class Details : public NotificationDetails {
public:
  // TODO(erg): Our code hard relies on implicit conversion
  Details(T *ptr) : NotificationDetails(ptr) {} // NOLINT
  Details(const NotificationDetails &other)     // NOLINT
      : NotificationDetails(other) {}

  T *operator->() const { return ptr(); }
  // The casts here allow this to compile with both T = Foo and T = const Foo.
  T *ptr() const { return static_cast<T *>(const_cast<void *>(ptr_)); }
};

} // namespace base
